When the enormous Cordeaux Dam - second of the four great dams on the Upper Nepean Rivers - was completed in 1926, it quickly became an attraction for tourists and picnickers who marvelled at the engineering masterpiece.

As if the natural wonders of the ridges and gorges of the Upper Nepean were not enough, man's hand was invoked to bring the wilderness in reach of the city dweller - close, but not too close.

At the entrance to the dam the bush was cleared and a vast picnic area grew.

Today the Cordeaux Dam has picnic and barbecue facilities sufficient to host a world-wide reunion of the Smith family.

Amid a vast lawn area with shade trees we counted over 70 tables (seating for over 500 - with a number under cover), 28 barbecues (most electric), clean toilet blocks, a children's playground, innumerable benches and water taps, and acres of grounds for the kids to play on.

A Great Picnic Area.

In the 30s and later the 50s Cordeaux and other reserves around the dams, were popular with motoring families escaping the city for a day in the bush.

Here was sunshine, blue sky (we forget the dense smog over the city produced by the coal fires of former ages), fresh air, the excitement of being near (not in) the bush, space to move, and the chance to indulge in the great Australian pastime - the picnic and barbecue - all within a day's drive.

To cap the day's excitement, there was the spectacular Cordeaux Dam with its vast masonry and lake backed up behind it.

All of this is still there to be enjoyed today, but with the best of updated amenities.

Escaping the city in the modern age (same smog, only from cars now) is just as important now as it was for our grandparents' generation.

Close to the City.

Today the Cordeaux is only an hour from most of Sydney, and there couldn't be a better place for weekend outing.

Sure the facilities are on a vast scale here, but spread out over such a wide area as to make the family picnic an intimate occasion.

There is plenty of time for the older folks to sit around the tables and catch up on the latest news, while the kids play within safe view, and a walk down to the dam after lunch is a much more important part of the day's outing than cheating by driving.

The dam itself is imposing enough in an age jaded by men landing on the moon - particularly if the tourist realises it was built almost 3/4s of a century ago by men without the benefit of the modern machinery we take for granted.

The Great Dam.

The concrete battlements over the top of the dam hide a footing of vast stone blocks carved from the surrounding area and which make up the bulk of the dam itself.

Although built by engineers, the perceptive eye will notice the neo-classical and Art Deco influences of the entrance to the walkway over the top, and the structures on it.

The great columns suggest an origin in pre-classical times, their bulges and fluting harking back more to Ancient Egypt or Babylon than Greece.

By comparison much architectural engineering of more recent years is slave to function and budget, rather than style.

When the dam was built some architects in Australia were applying the fantasies of art deco and neo-classicism to their building (consider Burley Griffin), and this more modest structure is perhaps one of the few such examples to have stood the test of time. (It is not repeated so lavishly, for example, on the later Avon Dam.)

You might also notice a little room to the right inside the entrance. Here once presided a keeper and guide, who would extract from the curious a small sum to enjoy the thrill of walking across to the other side. (Such a kiosk once also existed on the Sydney Harbour Bridge.)

Fun for the Family - Free!

All this today is now free, courtesy of the Sydney Catchment Authority - the government authority which oversees the dams and the catchment areas.

It doesn't have quite the magic of past times - with guides, and gardeners to dress up the landscape with well-kept gardens and paths for the bright young things of an earlier age. But if you look hard enough you can see where they've been.

Today it's all do it yourself. But, if you want to escape the inexorable life in the suburbs - just for half a day - bundle the family into the car, head out of town, and spend a refreshing break at Cordeaux Dam.

You might even want to stay longer, or come back again to the delights of the Wollondilly Region.

While you are gazing at the dam you are only seeing part of this engineering marvel.

At Pheasants Nest (near where the roadhouse is on the freeway) water is diverted to the Nepean Tunnel (7.5kms long) to the Cataract River at Broughton Pass Weir. (Between Appin and Wilton.)

From there it flows through Cataract Tunnel, to the Upper Canal where it flows some 57 kilometres to the Prospect Water Filtration Plant near Prospect Reservoir, and from here it is reticulated throughout the city.

How to get there.

From Wollongong: take the freeway north towards Sydney, then the Picton turnoff. The entrance is about 10 minutes on your left.

From Sydney: take the M5 towards Canberra. Past Campbelltown, take the Wollongong turnoff at Picton Road. The entrance is about 10 minutes on your right.

Cordeaux Dam is open 7 days a week, 10.00am to 5.30pm. (Closes 7.00pm weekends and Public Holidays during Daylight Saving Time.) Entrance is free.

For more information contact the Sydney Catchment Authority on (02) 4640 1200 during business hours Monday to Friday contact 13 20 52 or see their website - www.sca.nsw.gov.au.